Snap switch having s-shaped spring leaf on the movable switch blade thereof

ABSTRACT

This application discloses a switch mechanism and method in which an S-shaped spring leaf is secured to the movable blade end of a snap blade of a switch construction. The spring leaf is originally straight and is secured to the blade end in straight condition and then is bent into an S shape. The S-shaped spring has reversely bent ends on opposite sides of a central leaf portion that is attached to the blade end by means of movable contact heads. The reversely bent leaf ends engage stationary contacts on opposite sides of said reversely bent ends and on opposite sides of the movable blade end. The leaf ends maintain contact with the respective stationary contact and the respective movable contact head during vibration or chatter until the snap over of the blade occurs. Contact bounce after snap over is also dampened by the other reversely bent leaf spring end, when it engages the other stationary contact. The blade may be a snap blade, with a C-chaped spring, and may be actuated by a plunger. The entire switch construction may be contained within a switch casing.

United States Patent [72] Inventor John W. Habecker Grove City, Ohio [2!] Appl. No. 720,039

[22] Filed Apr. 10, 1968 [45] Patented Feb. 16, 1971 [73] Assignee Robertshaw Controls Company Richmond, Va.

[54] SNAP SWITCH HAVING S-SHAPED SPRING LEAF ON THE MOVABLE SWITCH BLADE THEREOF Primary Examiner-David Smith, Jr. AttarneysAuzville Jackson, Jr., Robert L Marben and Candor, Candor & Tassone ABSTRACT: This application discloses a switch mechanism and method in which an S-shaped spring leaf is secured to the movable blade end of a snap blade of a switch construction. The spring leaf is originally straight and is secured to the blade end in straight condition and then is bent into an S shape, The S-shaped spring has reversely bent ends on opposite sides of a central leaf portion that is attached to the blade end by means of movable contact heads. The reversely bent leaf ends engage stationary contacts on opposite sides of said reversely bent ends and on opposite sides of the movable blade end. The leaf ends maintain contact with the respective stationary contact and the respective movable contact head during vibration or chatter until the snap over of the blade occurs. Contact bounce after snap over is also dampened by the other reversely bent leaf spring end, when it engages the other stationary Contact. The blade may be a snap blade, with a C-shaped spring, and may be actuated by a plunger. The entire switch construction may be contained within a switch casing.

PATENTEDFEBIGISTI j 3564.182

FIG-l I 29 66 67% so 62 22 59 7 4 82 28 l 26 v v INVENTOR JOHN w. HABECKER BY 3 2 HIS ATTORNEYS SNAP SWITCH HAVING S-SHAPED SPRING LEAF ON THE MOVABLE SWITCH BLADE THEREOF This invention relates to a vibration proof snap switch mechanism.

A feature of this invention includes a vibration proof movable contact member or snap blade of a switch mechanism and method of making the same which includes securing an unbent, substantially straight spring leaf to one side of the movable end of said movable contact member or blade of such switch mechanism in alignment with opposite movable contact heads on opposite sides of said movable end, and then reversely bending the leaf ends of said straight spring leaf over said movable contact heads, and producing such switch mechanism with opposite stationary contacts and with the inner surfaces of such reversely bent leaf ends alternately in engagement with respective ones of said opposite movable contact heads and with the outer surfaces of such reversely bent leaf ends alternately and simultaneously in engagement with respective ones of said opposite stationary contacts.

Another feature of this invention includes a switch mechanism having a movable contact member or snap action blade with a movable member end which receives and holds an S-shaped spring leaf which has acentral leaf portion conductively secured to the contact member end, and with the spring leaf having reversely bent leaf ends on opposite sides of said central leaf portion.

Another feature of this invention provides that the central leaf portion will be secured to the blade end by means of electrically conductive fastening means, such as rivet means, which may also be the movable contact heads of the blade.

Another feature of this invention includes the attachment of a straight or unbent spring leaf to a blade end, after which the spring leaf ends are reversely bent to opposite sides of the blade end and over the contact heads.

Other features of this invention become apparent from this I description, the appended claimed subject matter, and/or the accompanying drawings, in which:

FIG. 1 is a side view, partly in elevation, of a vibration proof snap switch mechanism according to this invention.

FIG. 2 is an end view of FIG. 1.

HO. 3 is a perspective view of the movable contact member orblade with the S-shaped spring leaf thereon.

' FIG. 4 is a top view of the switch blade, in enlarged scale, with the leaf spring in flat condition and secured to the blade end before being formed into an S-shaped spring leaf.

H6. 5 is a cross section along line 5-5 of HO. 4 and also showing the leaf spring formed into an S-shaped spring leaf in dotted lines with the reversely bent leaf spring ends bent over the movable contact heads.

FIG. 6 is an end view of a portion of HO. 4, with the leaf spring bent into S-shaped condition.

FIG. 7 is a partial cross section of the contact member, spring leaf, and stationary contacts shown in FIG. 1, and taken along the line 7-7 of FIG. 1, at the instant of first electrical connection with the lower electrical contact member.

FIG. 8 is a view similar to FIG. 7, and showing the movable contact member end at its lowest down position.

Certain words are used in this application to indicate direction, relative position, and the like. However, such words are used only in connection with the views of the drawings. lt is to be understood that the article may be moved to difierent positions so that the parts so described may be in entirely different direction, relative position, and the like. Examples of such words are upper, lower", vertical", horizontal, etc.

A switch mechanism 20, according to this invention, may have a movable contact member 22, which may be a flat snap spring blade, if desired. The movable contact member 22 may have a movable contact member or blade end 24 and a stationary contact member or blade end 26, which end 26 may be held by a rivet or screw receiving construction 28 in the insulative casing 30 of the switch mechanism or construction.

An S-shaped spring leaf 32 may have a central leaf portion 34 conductively secured to the said contact member 24 before said blade is secured in the casing 30. Such spring leaf may have reversely bent leaf ends 36 and 38 on opposite sides of such central leaf portion 34.

Stationary contacts 40 and 42 may be carried by the casing 30 on opposite sides of the outer sides of said reversely bent leaf ends 36 and 38. The contacts 40 and 42 are alternately engaged by the outer sides of said reversely bent'leaf ends 36 and 38, alternately electrically to connect said movable contact member or blade end 24 with said stationary contacts 40 and 42.

The central leaf portion 34 may be secured to the contact member or blade end 24 by electrically conductive fastening means 44. Such conductive fastening means 44 may be in the form of conductive rivet means, in which such conductive rivet means may be movable contact heads 46 and 48. The contact heads 46 and 48 are respectively and alternately engaged by the insides of said reversely bent leaf ends 36 and 38 when the outer sides of the reversely bent leaf ends 36 and 38 alternately and respectively engage the stationary contacts 40 and 42.

The movable contact member 22 may be in the form of a flat snap spring blade, and snapmeans 50 maybe provided to snap spring blade 22 alternately against the stationary contacts 40 and 42. Such snap means 50 may be in the form of a compression C-spring with one C-spring end 52 having a tongue and slot engagement with the blade end 24. The other C- spring end 54 may have a tongue and slot engagement with .the

stationarily held end 56 of the stiff pivot blade 58. The blade also may be held by the rivet and screw receiving construction 28 in the casing 30.

A plunger actuating means 60 rnay pass through a wall of shown, respectively to the rivet screw receiving construction 28 and blade 22, and to the stationary contacts 42 and 44 through the medium of stationary blades 80 and 82, which are secured to the casing 30.

In attaching the S-shaped spring leaf 32 to the blade end 24, a simple and economical method may be followed in which unformed, unbent, or straight spring leaf 32A, FIGS. 4 and 5, may be secured to the blade end 24 by means of one or both of the rivets or contact heads 46 and 48, as shown in full and dotted lines in FIGS. 4 and 5. Thereafter, the straight spring leaf 32A may be reversely bent, to provide the reversely bent leaf ends 36 and 38, as shown in dotted lines in FIG. 5, and in full lines in FIGS. 6, 7 and 8. This secures the straight spring leaf 32A to the blade end 24 by one or both of the movable, contact heads 46 and 48 and then places the reversely bent spring leaf ends 36 and 38 over the movable contact heads 40 and 42 in a very simple manner to provide a vibration proof snap switch mechanism by a very simple but effective method.

The spring leaf 32 may be made of a spring silver material or movable contact member or flexible snap blade switch mechanism 20 has thus been provided. The unbent, substantially straight spring leaf 32A is secured to one side of the movable end 24 of the movable member or blade 22 of the mechanism 20. The spring leaf 32A is secured to the blade end 24 in alignment with the opposite movable contact heads 46 and 48 on opposite sides of the movable member or blade end 24. Then the unbent leaf ends of this straight leaf 32A are reversely bent, as shown at 36 and38, over the movable contact heads 46 and 48. The switch mechanism 20 is provided with the stationary contacts 40 and 42 so that the inner surfaces of the reversely bent leaf ends 36 and 38 alternately can be in engagement with the respective ones of said opposite movable contact heads 46 and 48 and with the outer surfaces of said reversely bent leaf ends 36 and 38 also alternately and simultaneously in engagement with respective ones of said stationary contacts 40 and 42, as shown in the lower position in FIG. 8 and in the upper position in FIG. '1.

In the normal free position of FIG. 1, for example, or operated position of FIG. 8, for example, the spring leaf ends 36 and 38 will be alternately pressed against the respective movable contacts 46 and 48 and against the respective stationary contacts 40 and 42. Therefore, the main path of current is only through the thickness of the spring leaf end 38, at FlG. 8, for example, such as from stationary contact 42, through spring leaf end 38, movable contact head 48 and blade end 24, to connect conductors 74 and 76. As vibration or shock is applied to cause a chattering motion of the blade and the main moving contact 48, the spring leaf end 38 will tend to remain against the stationary contact 42 and maintain electrical conduction or circuit until the snap over action occurs to the position of FIG. 1.

Contact bounce after snap over will be dampened by the other spring leaf end 36 as it engages stationary contact 40. Such bounce will be reduced due to the spring leaf contact follower action which causes the spring leaf end 36 to engage the stationary contact 40 while the spring leaf end 36 is spread away from contact head 46, as shown in FIG. 7. An inverse action takes place when the movable contact member or blade end 24 moves downwardly from the stationary contact 40 to the stationary contact 42, and the spring leaf end 38 engages the stationary contact 42 while the spring leaf end 38 is spread away from the contact head 48, also as shown in FIG. 7.

A new, unobvious and improved vibration free switch mechanism has therefore been provided.

lclaim:

1. A switch construction having a movable contact member with a movable contact member end, said contact member having a longitudinal axis, an S-shaped spring leaf having a central leaf portion disposed transverse to said axis and conductively secured to said contact member end and having reversely bent leaf ends on opposite sides of said central leaf portion and said movable contact member end, and stationary contacts on opposite sides of and alternately engaged by the outer sides of said reversely bent leaf ends electrically to connect said movable contact member end with said stationary contacts, said stationary contacts and said bent leaf ends being in aligned relation along a straight line that is disposed substantially perpendicular to said longitudinal axis of said contact member.

2. A switch construction according to claim 1 in which said bent leaf ends are normally substantially parallel to said central leaf portion. 

1. A switch construction having a movable contact member with a movable contact member end, said contact member having a longitudinal axis, an S-shaped spring leaf having a central leaf portioN disposed transverse to said axis and conductively secured to said contact member end and having reversely bent leaf ends on opposite sides of said central leaf portion and said movable contact member end, and stationary contacts on opposite sides of and alternately engaged by the outer sides of said reversely bent leaf ends electrically to connect said movable contact member end with said stationary contacts, said stationary contacts and said bent leaf ends being in aligned relation along a straight line that is disposed substantially perpendicular to said longitudinal axis of said contact member.
 2. A switch construction according to claim 1 in which said bent leaf ends are normally substantially parallel to said central leaf portion. 